A cell is connected to a 10.0 Ohm resistor. The pd across the 10.0 Ohm resistor is 10.43 V.
A 4.00 Ohm resistor is connected in parallel with the 10.0 Ohm resistor. The pd across the 10.0 Ohm resistor falls to 7.87 V.
Calculate the emf and the internal resistance of the cell.
E = V + Ir
V = IR
The Attempt at a Solution
I tried to work out the total resistance in circuit 2. I got it as 2.86 Ohms. I then tried to work out the current in this circuit and got it as 2.75A. Using the information of volts, current and resistance I used Ohm's Law to try and work out the value of the internal resistor. I got it as 2.85 Ohms. However, when i used this in circuit 1 and tried to work out Emf, the two circuits did not match. Help?